Question 1

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A circular coil is placed inside a magnetic field and rotated clockwise to induce an emf. Which ONE of the following changes will increase the induced emf?
Question 1 Answer

A.
Rotating the coil slower

B.
Increasing the speed of rotation of the coil

C.
Decreasing the number of turns/windings of the coil

D.
Changing the polarity of the magnets

Question 2
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The induced emf in a coil is directly proportional to ___________
Question 2 Answer

A.
change in magnetic flux inside the coil.

B.
the rate of change of magnetic flux inside the coil.

C.
the rate of change of magnetic flux outside the coil.

D.
change in magnetic flux outside the coil.

Question 3
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In which ONE of the sketches below is the induced polarity of the coil CORRECTLY indicated?
Question 3 Answer

A.

B.

C.

D.

Question 4
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The magnitude of the induced emf across the ends of a loop is equal to the ______.
Question 4 Answer

A.
Thickness of the wire.

B.
Temperature of the wire.

C.
Radius of the loop.

D.
Rate of change the magnetic flux linkage with the wire.

Question 5
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A solenoid with 450 turns has a cross-sectional area of 176 cm2. It is positioned perpendicular to a uniform magnetic field of 0,72 T.
The flux through the solenoid is Answer 1 Question 5 Wb.
The induced emf in the solenoid is pulled out of the magnetic field in 0,22 s is Answer 2 Question 5V.

Question 6
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The ways to Blank 1 Question 6 magnetic field strength would be to Blank 2 Question 6 number of turns in the solenoid, increase Blank 3 Question 6 in the coil and to use a Blank 4 Question 6 core.

Question 7
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Look at the coil below:

If the magnet is moving out of the coil and the current is flowing through the galvanometer as shown, then the following would be correct:
A - Blank 1 Question 7
B - Blank 2 Question 7
C- Blank 3 Question 7
D - Blank 4 Question 7

Question 8
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Question text
A solenoid with 450 turns has a cross-sectional area of 176 cm2. It is positioned perpendicular to a uniform magnetic field of 0,72 T.
The flux through the solenoid is Answer 1 Question 8 Wb.
The induced emf in the solenoid is pulled out of the magnetic field in 0,22 s is

Answer 1

Here are the answers to your questions:

Question 1

Answer: B. Increasing the speed of rotation of the coil

• Increasing the speed of rotation of the coil will increase the rate at which the magnetic field lines are cut by the coil, thus increasing the induced emf.

Question 2

Answer: B. the rate of change of magnetic flux inside the coil.

• The induced emf is directly proportional to the rate of change of magnetic flux through the coil, as described by Faraday’s law of electromagnetic induction.

Question 3

Answer: (Cannot provide answer without sketches.)

• Please refer to the sketches you have to determine which one correctly indicates the induced polarity.

Question 4

Answer: D. Rate of change the magnetic flux linkage with the wire.

• The magnitude of the induced emf across the ends of a loop is equal to the rate of change of magnetic flux linkage with the wire, based on Faraday’s law.

Question 5

To calculate flux (Φ) through the solenoid and the induced emf (E):

1. Calculate flux: \[ \Phi = B \cdot A \cdot N \] Where:

   • \(B = 0.72 , T\) (magnetic field)
   • \(A = 176 , \text{cm}^2 = 0.0176 , \text{m}^2\) (cross-sectional area)
   • \(N = 450\) turns

   \[ \Phi = 0.72 \cdot 0.0176 \cdot 450 = 5.728 , Wb \]

2. Calculate induced emf: \[ \text{Induced emf} (E) = -\frac{\Delta \Phi}{\Delta t} \] Given that the field is pulled out in \(0.22 , s\), if we assume the change in flux is equal to \(\Phi\): \[ E = -\frac{5.728}{0.22} \approx -26.00 , V \] Since we are interested in the magnitude: Answer 1: 5.728 Wb and Answer 2: 26.00 V.

Question 6

Fill in the blanks related to ways to increase magnetic field strength:

• Blank 1: increase
• Blank 2: the
• Blank 3: current
• Blank 4: ferromagnetic

Question 7

Answer: (Cannot provide answer without details on the galvanometer's indications.)

• Please refer to the information available regarding the galvanometer and specify if you can provide details on its direction or polarity.

Question 8

(Same as question 5)

1. Calculate the flux through the solenoid:

   • Answer 1: 5.728 Wb.

2. Calculate the induced emf in the solenoid:

   • Answer 2: 26.00 V.

Let me know if you have further questions or need clarifications!